Author Topic: PP750 Artemis Tear Down and Tune Up (Read 35263 times))

Thane · « **Reply #20 on:** March 09, 2020, 03:49:44 PM »

Decided to open up the air path:
Regulator to plenum <3mm to 5mm
Valve is 5.9 mm with 2.8 mm poppet shaft
Valve port 3mm to 4.5 mm
Transfer port 3mm to 4mm
Barrel Port 3mm to 3.5mm (filled channel with epoxy, single aligned port tapers from 4.5 to 3.5)

Also increased plenum diameter by 1mm (20% increase in a very tiny plenum).

Noticed hammer was trapping volume of air against valve face (suction when removed), slotted hammer. Also notice off center valve stem.

Netted a 10.5% increase in power (37% power increase over best stock string).

With JSB Heavy 10.3 gr it makes a flat 23 shot string at 13.6 FPE.

Thane · « **Reply #21 on:** March 09, 2020, 03:58:37 PM »

Quote from: Backyard Shootr on March 09, 2020, 08:56:00 AM

I was going to buy one. But after looking at your photos and seeing your problems I think I will pass this one up.

To be fair I am pushing this airgun well beyond most, but certainly not as much as some of you

.

PP750 is not intended to be a hand cannon and comes with a very respectable tune in 700FPS 9-10 FPE a very decent pistol speed making it a 30 yard specialist.

I am tinkering for fun, testing limits by exceeding them, then fixing it.

I can't wait for others to jump in, hopefully adding to this thread whatever mods they work up.
That's where the fun is for me, and occasionally shooting...

Thane · « **Reply #22 on:** March 18, 2020, 08:17:35 PM »

Arts n crafts day for the PP750.

Found a guy on Etsy doing some interesting knife scales with exotic woods, multi-colored resins, aluminum hex cell...

Shaped a set of his blanks to beef up the thin factory handle, thumb ledge and bling factor.

Added a red LED flashlight for some night time visitors...

anti-squirrel · « **Reply #23 on:** March 18, 2020, 10:40:47 PM »

Those look great.

Between the power level you've achieved and the overall build/tune, you've got yourself a sharp-looking compact carbine for close-in vermin/pesting. I love it!

Warburrito · « **Reply #24 on:** March 19, 2020, 07:21:53 AM »

Agree...lookin really good!

Thane · « **Reply #25 on:** March 19, 2020, 02:33:29 PM »

Thanks!

It is a fun gun to shoot and tinker with, plenty of room for modifications. Wes has to be itching to ship these, and I look forward to getting some company.

There is going to be an onslaught of modifying, it is just so easy to break down, adjust and re-assembly.

Aeroman · « **Reply #26 on:** April 25, 2020, 02:40:29 PM »

Quote from: Thane on March 06, 2020, 06:08:12 PM

Quote from: Nomadic Pirate on March 06, 2020, 05:59:55 PM
So, do you think there's a chance to get her to 20 FPE ?

At .177 with an 8" barrel it's going to take some opening up, lose the regulator, increase hammer mass...?
I am going to pull the regulator stack and adjustment screw to shoot an unregulated string to see if it's ports slowing it down. Could also be small plenum volume, light hammer... I doubt the stock spring/hammer could open the valve @ 250 BAR.

Looking forward to others jumping in, lots of talent here.

Did you ever pull the reg stack and try it unregulated... Dying to know how that would perform...

Thane · « **Reply #27 on:** April 25, 2020, 03:16:25 PM »

I did some testing with the reg stack removed. Difficult to seal air tube, takes a large/thin oring to hold air at pressure which kept pressing it out like taffy. I could only hold 2400 psi and made some 16FPE shots, only 2 FPE better than highest tune with regulator.

Next step would be to turn a channel to retain larger oring to make full pressure, increase hammer mass as it was struggling to crack the PEEK valve at 2400 PSI, increase spring force.

Plenty of room for exploring...

barreira · « **Reply #28 on:** May 13, 2020, 12:45:00 PM »

Quote from: Thane on March 18, 2020, 08:17:35 PM

Arts n crafts day for the PP750.

Found a guy on Etsy doing some interesting knife scales with exotic woods, multi-colored resins, aluminum hex cell...

Shaped a set of his blanks to beef up the thin factory handle, thumb ledge and bling factor.

Added a red LED flashlight for some night time visitors...

It would be nice to know how you add the LDC to the shroud/barrel.

Thank you

Thane · « **Reply #29 on:** May 13, 2020, 03:26:32 PM »

Quote from: barreira on May 13, 2020, 12:45:00 PM

It would be nice to know how you add the LDC to the shroud/barrel.

Thank you

I turned an adapter from aluminum on a lathe months ago.

Donny FL now has PP750 adaptors available:

https://donnyfl.com/collections/adapters/products/pp750-1-2-x-20-adapter-a63

Warburrito · « **Reply #30 on:** May 13, 2020, 03:30:04 PM »

Don't have one yet, but I think all it is is a 1/2-20 threaded tube. Any adapter for an Umarex Gauntlet should work. Thats what I bought. Can't wait for a pistol to attach it to.

get2anthony@gmail.com · « **Reply #31 on:** July 10, 2020, 09:33:56 PM »

Quote from: Thane on March 05, 2020, 05:34:11 PM

Scoped with a UTG Bugbuster 3-12x32mm Side Objective, feather weight and adjustable to 3 yards. Scope height is 1.66" may be able to lower another 5 mm to bring my near zero in a meter or so.

Thane, Thanks for all the pictures, tear downs and commentary on this platform. The Bugbuster looks like it works really well!

I've recently acquired one and am curious how you removed the plastic end-of-barrel sight from the barrel shroud? Did you have to break it to get it off?

Thanks!

Thane · « **Reply #32 on:** July 10, 2020, 10:13:24 PM »

It is A cap threaded into the shroud.
Takes some coaxing the first time off.

USAFANG6799 · « **Reply #33 on:** July 11, 2020, 01:48:19 PM »

Thane - do you think the PP750 is better suited as a .177 or a .22 given your experience with the .177?
Or is it too early to tell yet?
I ordered a .22 from Wes.

bear air · « **Reply #34 on:** July 11, 2020, 02:22:38 PM »

I also have a 22 caliber one coming from Wes. Thanks for all the photos and testing. Very nice little pistol/carbine Thane. Those handle scales are awesome.

Thane · « **Reply #35 on:** July 11, 2020, 05:57:27 PM »

I also have a .22 on order from Wes

.177 appears to have a small plenum volume, hoping the .22 is increased.

The baffles do a reasonable sound reduction in .177, @ .22 expect more noise.

Have to wait and see how it performs out of the box.

bear air · « **Reply #36 on:** July 11, 2020, 06:01:10 PM »

I'll probably use a DonnyFL Tanto on it.

superchikn · « **Reply #37 on:** July 11, 2020, 08:36:23 PM »

Subscribing! Cannot wait till mine gets here.

Thane · « **Reply #38 on:** July 15, 2020, 11:26:06 PM »

Like most budget guns the cocking action is not silky smooth. While it does smooth out a bit with use, some polishing and lube, there is definite coarseness to outright binding that can occur. This is exaggerated with higher spring tension, so it's time.

I first suspected the pellet probe dragging on it's metal collar, which could be replaced with a longer MDS collar which has helped Hatsan Flashpups. Nope, probe end completely retracts past collar and is only supported by the 1" ± wide portion of probe which has a machine bolt stud that catches against hammer sear ledge. When cocking the hammer spring force loads the bolt stud, skewing the pellet probe and dragging/binding in block. The machine bolt also had a very small overlap of hammer ledge wearing to a chamfer, I'm sure it was riding up onto the outer portion of the ledge making some occasional serious binding. Adding a 0.020" shim under machine bolt space increased the engagement. It is still rough cocking, but no more binding.

Some PTFE slides let into the probe would certainly help.

B.Guns. · « **Reply #39 on:** July 16, 2020, 10:09:04 AM »

Can you tell us more on how you made the grips?
Thanks!

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PP750 Artemis Tear Down and Tune Up

Author Topic: PP750 Artemis Tear Down and Tune Up (Read 35263 times))